Descent controller with safety brake

Abstract

A descent controller for lowering a workman or other person along a vertically extending rope from an elevated position to a relatively lower position includes a friction device that may be in the form of a cylinder having a plurality of turns of rope wrapped therearound or a plurality of spaced apart horizontal bars with the rope woven between the bars. The friction device interacts with said rope to retard the movement of the controller along the rope. A lever operated pawl is mounted beneath the friction device and is used by the workman to applying an adjustable force on said rope in order to control his descent down the rope. A centrifugal brake is mounted below the lever centrifugal brake. The centrifugal brake includes a wheel mounted for rotation and has the rope passing around at least a portion of said wheel. Included within the brake is a pawl brake mounted for rotation with the wheel and a fixed stop member. Upon sensing rapid rotation of the wheel, the pawl brake moves outwardly by centrifugal force to engage the fixed stop member and applies a positive stopping force on the wheel to prevent movement of the descent controller relative to said rope thereby preventing accidental freefall.

I claim:  
     
       1. A descent controller for lowering a rope supported load from an elevated position to a relatively lower position, said controller including a friction means interacting with said rope for retarding the movement of said controller along said rope, said friction means having an upper end and a lower end, means mounted adjacent the lower end of said friction means for applying an adjustable force on said rope, and a centrifugal brake means mounted below said force applying means for positively stopping the movement of said descent controller relative to said rope. 
     
     
       2. The descent controller as defined in  claim 1  wherein said friction means is comprised of a cylinder of a length adapted to receive a plurality of turns of rope wrapped therearound. 
     
     
       3. The descent controller as defined in  claim 2  further wherein said means for applying an adjustable force includes a fixed wall segment and a movable pawl and wherein said rope is adapted to pass between said pawl and said wall segment. 
     
     
       4. A descent controller as defined in  claim 3  therein said pawl is spring biased toward said wall. 
     
     
       5. A descent controller as defined in  claim 4  further including a manually operative lever secured to said pawl, said lever being adapted to move said pawl away from said wall and rope to reduce the force on said rope. 
     
     
       6. A descent controller as defined in  claim 3  wherein said wall is curved so as to follow the contours of a portion of the rope. 
     
     
       7. A descent controller as defined in  claim 3  wherein said pawl includes a face that is adapted to engage said rope to force the same against said fixed wall segment. 
     
     
       8. A descent controller as defined in  claim 7  wherein said face of said pawl is substantially parallel to said fixed wall segment. 
     
     
       9. A descent controller as defined in  claim 2  wherein said centrifugal brake means includes a wheel mounted for rotation below said cylinder, said rope passing around at least a portion of said wheel. 
     
     
       10. A descent controller as defined in  claim 9  wherein said wheel includes means for gripping said rope passing therearound. 
     
     
       11. A descent controller as defined in  claim 10  wherein said centrifugal brake means includes a pawl brake mounted for rotation with said wheel and a fixed stop, said pawl brake being spring biased away from said fixed stop. 
     
     
       12. A descent controller as defined in  claim 11  wherein said pawl brake moves outwardly by centrifugal force to engage said fixed stop upon rapid rotation of said wheel. 
     
     
       13. A descent controller as defined in  claim 1  wherein said friction means is comprised of a plurality of spaced apart horizontal bars and wherein said rope is adapted to be woven between said bars. 
     
     
       14. A descent controller as defined in  claim 13  further wherein said means for applying an adjustable force includes a fixed wall segment and a movable pawl and wherein said rope is adapted to pass between said pawl and said wall segment. 
     
     
       15. A descent controller as defined in  claim 14  wherein said pawl is spring biased toward said wall. 
     
     
       16. A descent controller as defined in  claim 15  further including a manually operative lever secured to said pawl, said lever being adapted to move said pawl away from said wall and rope to reduce the force on said rope. 
     
     
       17. A descent controller as defined in  claim 14  wherein said wall is curved so as to follow the contours of a portion of the rope. 
     
     
       18. A descent controller as defined in  claim 14  wherein said pawl includes a face that is adapted to engage said rope to force the same against said fixed wall segment. 
     
     
       19. A descent controller as defined in  claim 18  wherein said face of said pawl is substantially parallel to said fixed wall segment. 
     
     
       20. A descent controller as defined in  claim 13  wherein said centrifugal brake means includes a wheel mounted for rotation below said friction means, said rope passing around at least a portion of said wheel. 
     
     
       21. A descent controller as defined in  claim 20  wherein said wheel includes means for gripping said rope passing therearound. 
     
     
       22. A descent controller as defined in  claim 21  wherein said centrifugal brake means includes a pawl brake mounted for rotation with said wheel and a fixed stop, said pawl brake being spring biased away from said fixed stop. 
     
     
       23. The descent controller as defined in  claim 22  wherein said pawl brake moves outwardly by centrifugal force to engage said fixed stop means upon rapid rotation of said wheel.